A Quick Primer for CO People Entering Shell (and Other Interested People)
There're several different species of People, none of which can breed with each other. So the only 'hybrids' are weird mutants.
Species
The Bare People. Basically humans, not much more to say about them. Not inherently magical, they have to learn and use spells. Unless they're mutants.
The Beast People. A wild assortment of mammal and humanoid traits. Treated as one species because they can all interbreed, oddly enough. Usually mutts--not having traits of a single animal species. Though a few distinct races've emerged. Not inherently magical, though they might have abilities possessed by assorted mammals. Some suspect them of originally being Chaos creatures, but they've long since became natural beings.
The Tailed People. Created by a god preferring a long sleek form. Pretty much the universal traits are having a humanoid torso and a tail instead of lower legs. Despite being the closest analogues to mermaids and nagas, they don't have any human-like skin or hair. Instead, they have scales or amphibian skin, and sometimes crests or fins. Fish, reptile, and amphibian traits have been put within their genes, and they can transform (taking a few hours to days) to exhibit the desired ones. All identical in genes and all androgynous, variety pretty much results from them choosing different traits to exhibit. Unless one's a mutant weirdo.
The Winged People. Covered with warm feathers and having slender features but otherwise human-like. The only people with natural flight, generally. Wings are shimmering crystalline things that can expand at will from tiny to the size of great sail. Can fly at any wing size, larger wings just take less energy to fly with. Potent air magics. Rare on the ground--they mostly live high among the highest clouds in floating Utopian cities built out of ice. Winged Folk are one of the rare examples of a god actually successfully creating a people that can live harmoniously. You can guess why they tend to avoid the ground.
The wide prevalence of humanoid species can be explained by "Gods like stealing ideas from each other, and it happened to be a practical tool-using shape."
Not actually species
Undead. They can be of any species. Essentially, anyone who's stubbornly sticking around despite terminated life functions is undead. Typically their souls are bound to the remains of their old bodies or to some mobile object such as a doll or suit of armor. Ghosts exist but usually are attached to some anchor. Anchorless ghosts are rare. All undead need energy--some steal it from living things, others draw it directly from Chaos. To be undead is an unnatural state of being. Some mind this and some don't.
Mutants. Any species. Pretty much one of the perils of living in a world touched by Chaos. The extremely wildcard mutant category is why most CO agents would come through with little change to their forms and abilities. For example, Sonic would be a mutant blue Beast Person with the same superspeed. He would also be mistrusted at best in most countries, at worst targeted for elimination as a dangerous Chaos monster. Luckily the gate exits in Haven, where they don't care if you're a pink-eyed flying worm monster as long as you don't cause trouble. Though the pink-eyed flying worm monster might get a few odd looks because that's pretty weird even for Haven.
Magical creatures. A broad spectrum, it's hard to come up with any generalizations. The division between this and Chaos creatures is widely disputed. Beings established long enough to be stable tends to get labeled as a magical being. Usually each one is unique.
Chaos creatures. Unpredictable. Dangerous. Or they could just fall apart in a bizarre fashion, or spend decades doing something harmless with a singlemindedness. Hard to tell what one will do. Some seem to be created directly from Chaos (usually the most bizarre and incomprehensible ones), while others're Shell creatures that've been warped beyond the point their original species are recognizable.
Magic
Anyone can use standard spells, but most people only know the simple practical stuff. Like starting fires and removing spots, or mild blessings and wards. Advanced stuff takes work to master. Magic tends to use symbolic rituals, often utilizing some object connected to what one's doing. A lot of it's random cobbled together stuff. In general, magic often works a lot like folklore.
Then there is chaos magic. Its potential is infinite. That means it can be anything imaginable, including something you didn't want. Really really didn't want. Controlling it requires the skill to collapse the infinite possibilities into one single possibility and the absolute and utter focus upon what you want to happen. Not to mention pretty complete imagination of the results. Have fun with that. People making heavy use of Chaos magic tend to have short lives or end up... weird if they survive for a long time.
Usually successful 'chaos mages' make up rituals to help them focus on the results. Widely enough used rituals can become spells integrated into the world's laws itself. And the world becomes a little less recognizable.
Technology
Tech level is about 16th century Europe. Slow reloading gunners protected by pikes. Cannons. Printing presses. Astrolabes. Mechanisms frequently augmented or supported by magic.
Gods
To live in accordance with the wills of the gods is to be blessed and to be protected from Chaos. In Shell, this is actually true (life does go smoother if you do that). It's a bad idea to insult any god, unless you have another god to protect you or are pretty strong. Also, people get really pissed off. Religion and customs are important to most people of Shell. There are many different gods worshiped across Shell by different people.
Haven
The current gate exits in the nation of Haven, which has enough weird people that it's not hard to avoid notice (think heavily cosmopolitan cities and you get an idea of how blase people are). It's generally a bad idea to insult any gods anyway (this holds true everywhere in Shell). Also, the Justicars working for the God Justice don't appreciate attempts to cause harm to or deceive those obeying the laws--those are the only actual laws and they are enforced with an iron but fair fist. Always fair. Ruthlessly fair.
More specifically, the gate exits in Newport, a port city as you can guess. One of the largest cities in Haven. Like most towns in Haven, there's no central municipal planning. Have fun getting lost in randomly placed streets. Also, since the gate's in the temple of Zephyr, you might come across an embarrassing ceremony. Like people dancing around in a drunken state of undress.
Vacation Destinations (because we know how popular vacations are with CO employees)
Haven, being a coastal nation in a really warm climate, has nice beaches. Also, good seafood. And the water's more pure than usual because the aquatic citizens get really pissed off about pollution.
Species
The Bare People. Basically humans, not much more to say about them. Not inherently magical, they have to learn and use spells. Unless they're mutants.
The Beast People. A wild assortment of mammal and humanoid traits. Treated as one species because they can all interbreed, oddly enough. Usually mutts--not having traits of a single animal species. Though a few distinct races've emerged. Not inherently magical, though they might have abilities possessed by assorted mammals. Some suspect them of originally being Chaos creatures, but they've long since became natural beings.
The Tailed People. Created by a god preferring a long sleek form. Pretty much the universal traits are having a humanoid torso and a tail instead of lower legs. Despite being the closest analogues to mermaids and nagas, they don't have any human-like skin or hair. Instead, they have scales or amphibian skin, and sometimes crests or fins. Fish, reptile, and amphibian traits have been put within their genes, and they can transform (taking a few hours to days) to exhibit the desired ones. All identical in genes and all androgynous, variety pretty much results from them choosing different traits to exhibit. Unless one's a mutant weirdo.
The Winged People. Covered with warm feathers and having slender features but otherwise human-like. The only people with natural flight, generally. Wings are shimmering crystalline things that can expand at will from tiny to the size of great sail. Can fly at any wing size, larger wings just take less energy to fly with. Potent air magics. Rare on the ground--they mostly live high among the highest clouds in floating Utopian cities built out of ice. Winged Folk are one of the rare examples of a god actually successfully creating a people that can live harmoniously. You can guess why they tend to avoid the ground.
The wide prevalence of humanoid species can be explained by "Gods like stealing ideas from each other, and it happened to be a practical tool-using shape."
Not actually species
Undead. They can be of any species. Essentially, anyone who's stubbornly sticking around despite terminated life functions is undead. Typically their souls are bound to the remains of their old bodies or to some mobile object such as a doll or suit of armor. Ghosts exist but usually are attached to some anchor. Anchorless ghosts are rare. All undead need energy--some steal it from living things, others draw it directly from Chaos. To be undead is an unnatural state of being. Some mind this and some don't.
Mutants. Any species. Pretty much one of the perils of living in a world touched by Chaos. The extremely wildcard mutant category is why most CO agents would come through with little change to their forms and abilities. For example, Sonic would be a mutant blue Beast Person with the same superspeed. He would also be mistrusted at best in most countries, at worst targeted for elimination as a dangerous Chaos monster. Luckily the gate exits in Haven, where they don't care if you're a pink-eyed flying worm monster as long as you don't cause trouble. Though the pink-eyed flying worm monster might get a few odd looks because that's pretty weird even for Haven.
Magical creatures. A broad spectrum, it's hard to come up with any generalizations. The division between this and Chaos creatures is widely disputed. Beings established long enough to be stable tends to get labeled as a magical being. Usually each one is unique.
Chaos creatures. Unpredictable. Dangerous. Or they could just fall apart in a bizarre fashion, or spend decades doing something harmless with a singlemindedness. Hard to tell what one will do. Some seem to be created directly from Chaos (usually the most bizarre and incomprehensible ones), while others're Shell creatures that've been warped beyond the point their original species are recognizable.
Magic
Anyone can use standard spells, but most people only know the simple practical stuff. Like starting fires and removing spots, or mild blessings and wards. Advanced stuff takes work to master. Magic tends to use symbolic rituals, often utilizing some object connected to what one's doing. A lot of it's random cobbled together stuff. In general, magic often works a lot like folklore.
Then there is chaos magic. Its potential is infinite. That means it can be anything imaginable, including something you didn't want. Really really didn't want. Controlling it requires the skill to collapse the infinite possibilities into one single possibility and the absolute and utter focus upon what you want to happen. Not to mention pretty complete imagination of the results. Have fun with that. People making heavy use of Chaos magic tend to have short lives or end up... weird if they survive for a long time.
Usually successful 'chaos mages' make up rituals to help them focus on the results. Widely enough used rituals can become spells integrated into the world's laws itself. And the world becomes a little less recognizable.
Technology
Tech level is about 16th century Europe. Slow reloading gunners protected by pikes. Cannons. Printing presses. Astrolabes. Mechanisms frequently augmented or supported by magic.
Gods
To live in accordance with the wills of the gods is to be blessed and to be protected from Chaos. In Shell, this is actually true (life does go smoother if you do that). It's a bad idea to insult any god, unless you have another god to protect you or are pretty strong. Also, people get really pissed off. Religion and customs are important to most people of Shell. There are many different gods worshiped across Shell by different people.
Haven
The current gate exits in the nation of Haven, which has enough weird people that it's not hard to avoid notice (think heavily cosmopolitan cities and you get an idea of how blase people are). It's generally a bad idea to insult any gods anyway (this holds true everywhere in Shell). Also, the Justicars working for the God Justice don't appreciate attempts to cause harm to or deceive those obeying the laws--those are the only actual laws and they are enforced with an iron but fair fist. Always fair. Ruthlessly fair.
More specifically, the gate exits in Newport, a port city as you can guess. One of the largest cities in Haven. Like most towns in Haven, there's no central municipal planning. Have fun getting lost in randomly placed streets. Also, since the gate's in the temple of Zephyr, you might come across an embarrassing ceremony. Like people dancing around in a drunken state of undress.
Vacation Destinations (because we know how popular vacations are with CO employees)
Haven, being a coastal nation in a really warm climate, has nice beaches. Also, good seafood. And the water's more pure than usual because the aquatic citizens get really pissed off about pollution.